Modification of downcomer in jameson flotation cell and its effect on performance

Jameson cell is a flotation device having high performance used especially for flotation of fine particles in all over the world. In the downcomer, which is the most important distinctive part, all sub-processes of flotation occurs and it significantly affects the flotation performance. The most effective factors determining the limit of floating particle size are the hydrodynamic events occurring in downcomer and the flow characteristic taking place at the exit of downcomer. In the frame of this study; the hydrodynamic events coming into existence in downcomer and in its way out were investigated in a detail. Additionally a model was developed to estimate the maximum floating particle size and a serial of radical modifications were carried out to increase the flotation performance of particles improving the model developed.In the present work, the first part analyzes the hydrodynamics within and exit of downcomer, and gives a broad definition of the attachment and detachment mechanisms. The stability of aggregates was also quantitatively investigated by defining the turbulence of particle-bubble assembly in medium and theoretical solutions to diminish the turbulence. The second part is related to the modification work designed by the use of fluid mechanics law to supply regular flow and related with model, defining the turbulence in a quantity and estimate the maximum floating particle size after modification in concern. The third and last part involves the research carried out to verify the model by means of experimental data. A series of flotation experiments were realized using the Jameson cell with modified downcomers.The experimental results showed the suitability of the modification mode of the downcomer and validity of the model used to estimate the maximum floating particle size. The maximum floating particle size of quartz mineral with contact angle of 50º increased from 128 ?m to 154 ?m by utilizing the modified downcomer instead of classical downcomer.